Notes:

In her temperament there is so much jealousy/envy that when
I feel ardor for the Nightingale,
even this doesn't please her. The theme
has no pleasure, but on this very theme the author has elsewhere said, as
has already passed before us, {60,10}. (227)

He says, I have an ardor for listening to the melodies of
the sweet singers of the garden, and that infidel is [habitually] suspicious
of this ardor of mine. Oh, if only I didn't have this ardor! (285)

The Nightingale's voice pleases me because in the Nightingale's
song is pain, and because of similarity (that is, I too am one of the people
of pain, with the temperament of a lover), in hearing his voice I feel pleasure.
At this, that infidel (the beloved) becomes suspicious. That is, 'while I'm
here, he feels that he doesn't love me completely; if he did, then he wouldn't
pay attention to anyone else'. Seeing this state of the beloved's, the lover
feels a longing: 'if only I didn't have such a taste for lamentation!'. (399)

FWP:

This unpretentious little verse surrounds itself with a nice
set of overtones and implications.
For the 'bird of the garden' par excellence is the
Nightingale, who is himself
a lover (of the rose) and thus a fellow-sufferer with other tormented lovers.
And the lover has the taste 'to this extent', which seems in the context to
be a substantial one.

The verse points up the lover's dismal situation: even something
so innocent as his listening to a bird sing is enough to excite the beloved's
possessive jealousy and cruelty. And then, his response is not resentment,
defiance, or stoicism-- but a morbid wish that he didn't have even this innocent,
simple little desire, since it angers her (however unreasonably).

There's also a clever Catch-22 here: the beloved's cruelty
and suspicion make the lover mournful, and incline him toward the melancholy
songs of the Nightingale; but this inclination on his part is exactly the
kind of thing that reinforces her irrational jealousy, and thus increases her cruelty
and suspicion.